Plasma generation is performed in semiconductor processing systems including those performing deposition and etching, (e.g., plasma enhanced deposition and etching). Traditional plasma generating systems include transformer coupled plasma (TCP) systems, which is also referred to as inductively coupled plasma (ICP) systems. In TCP/ICP systems, the plasma contains various types of radicals, as well as positive and negative ions. The chemical reactions of the various radicals, positive ions, and negative ions are used, for example, to etch features, surfaces, and materials of the substrate. During the etching process, for example, a chamber coil performs a function analogous to that of a primary coil in a transformer, while the plasma performs a function analogous to that of a secondary coil in the transformer. Plasma reaction and generation may not be uniform across the substrate. In particular, plasma may be generated in a ring region somewhere over the interior of the substrate. Taking a cross-section, the plasma generation across a radial of the substrate may be characterized with an “M” pattern, wherein the two peaks form the ring. As such, plasma generation is non-uniformly concentrated in a ring over the substrate, which results in non-uniform semiconductor processing across the width of the substrate.
In traditional RF ICP/TCP systems, the inductor coil has to be placed close to the plasma's dielectric window, which results in a strong capacitive voltage. For applications where the capacitive voltage is adverse, a Faraday shield design would have to be implemented, complicating the source and its operations.
The background description provided herein is for the purposes of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure
It is in this context that embodiments of the disclosure arise.